erl beam instrumentation - kek

ERL beam instrumentation

ERL beam instrumentation group

T. Mitsuhashi

S. HiramatsuT. KasugaT. Obina

M. TobiyamaT. NaitohT. FurukawaM. Satoh

N. Nakamura

Developments of monitors

Developments of control including fs technology

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Beam instrumentation for the ELR

1. Profile measurementFluorescence screen

Optical profile monitor by OTR or SRWire scanner SEM or Compton scatteringHigh speed gated camera

2. Position measurement BPM electronicBPM SR or OTR

3. Intensity measurementDCCT, Differential DCCT

Photocathode, Faraday cupSR or OTR intensity monitor

4. Emittance measurementFluorescence screen with slitWire scannerInterferometer SR or OTR

5. Temporal structureStreak camera SR or OTRIncoherent intensity interferometer SR or OTRCSR interferometer CSRBLM opto-electric

6. HaloWire scannerCoronagraph SR or OTR

7. Beam loss

ERL試験機のレイアウト

現在提案されている周回部のOptics案（原田）

長直線部の中心

Arc1部

Dispersion赤：ビームサイズ測定　　Emittance評価　　Halo測定　　Dispersionなし緑：ビームサイズ測定　　Dispersion評価　　光学的ビーム位置　　測定PBPM青：Halo測定　　Dispersionあり　　

全ての四極にはBPMをつけるArcの中心にはBPMがつけられるか？

5m

0m

0m

6m

SR1

SR2

SR3 SR4

BPM蛍光板、OTR

入射部および加速空洞直線部

入射部

蛍光板またはスリット付蛍光板(emittance 評価)

BPMストリップラインワイヤースキャナーまたはSEM

OTR,蛍光板

BPM

cavity BPMBLM (one pass, Opto-electric type)

Test port for developments

differential DCCT for current valance

Arc2部

SR5

SR6SR7

BPM

蛍光板,OTR

Dump line

BPM

蛍光板

SRI, Streak cameraHalo, profile

3SR

or OTRPosition, profile

6Fluorescence screen

Position1BPMSR

Position, timing, phase8BPMArc1

Position, profile1OTR

Position, profile3Fluorescence screen

Position, timing, phase3BPMStraight1

cavity

Position, profile4Fluorescence screenMerger

Emittance, Halo1Wire scannerSEM mode

Emittance2Fluorescence screen (with slit)

Position, profile2Fluorescence screenPosition, timing2BPM(strip line)Injector

CommentResolutionAccuracyDevice

Position3BPM

Position, profile4Fluorescence screen

Dump line

Bunch by bunchCurrent

1WCM

DC current1DCCT

Current difference１Differential DCCTOthers

SRI, Streak cameraHalo, profile

3SR

or OTRPosition, profile

6Fluorescence screen

Position1BPMSR

Position,timing, phase

8BPMArc2

Bunch lengthBLM(Opto-electric)

developmentTest section

Accurate Position2Cavity BPM

Position, timing, phase

2BPMStraight 2

Test facility for shortpulse beam at PFBT

Development of beam monitors Development of fs technology

現状PF-BT

電荷制限WCM６．５W

６５Ｗビーム

６.5Ｗビーム

０．６5Ｗビーム

インターロック

電荷制限WCM

０．６５W

Test port for the development of beam monitors

0.6ps to 4psec 60W (2.5GeV,1nc, 25pps)

BH31 入口εx=40 (nm*rad)εy=13 (nm*rad)

σz=1.4 (mm)=4.2(psec)σε=1.0 x 10-3

R56=1.0 (m) Normal : BK-BH31間

εx=40 (nm*rad)εy=13 (nm*rad)

σz=0.99 (mm)=3.3(psec)σε=1.0 x 10-3

BH31 入口

R56=0.0 (m) Isochronous: BK-BH31間

εx=40 (nm*rad)εy=13 (nm*rad)

σz=0.17 (mm)=0.57(psec)σε=10.0 x 10-3

BH31 入口

R56=0.1 (m)T566 = -0.11 (m) Bunch Compress: BK-BH31間

Beam instrumentation based on Optical and opto-electric method

Incoherent SR intensity Interferometry

forShort bunch mesurement

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⎡

⎟⎟

⎠

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⎛

⎟⎟⎠

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σδτ−−

στ+⎟⎟

⎠

⎞⎜⎜⎝

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τδτ−−σ=δτ

2p

2

p2

c

22

p124

exp2

11

*

4exp

2

11Kcount

We thus obtain coincidence count;

Illustration of intensity interference pattern with chaotic light pulse.

Illustration of intensity interference pattern with coherent light pulse.

Phase correlation peak in the center.

er

0.9

0.92

0.94

0.96

0.98

1

1.02

0 20 40 60 80 100

Corner-Cube Displacement (mm)

Pulse envelope length σp

Coherent length of wave pockets τc

Pulse envelope length σp is always longer than Coherent length of wave

pockets τc.

σp ≥ τc

We can measure the very short pulse length with intensity interferometry

with nearly no theoretical limit on temporal resolution.

Actual resolution will be limited by dispersion of the glass.

Coronagraph for halo measurement

Objective lens

Field lens

Baffle plate (Lyot stop)

Relay lens

Opaque disk

Anti-reflection disk

Baffle plates to reduce reflection

Optical layout of the coronagraph

65.8mA 61.4mA 54.3mA

45.5mA 35.5mA 396.8mAMulti-bunch

bunch current 1.42mA

Beam tail images in the single bunch operation at the KEK PF measured at different current

Single bunch 65.8mA

Exposure time of CCD : 3msec

Exposure time of CCD : 100msec

Intensity in here : 2.05x10-4

of peak intensity

2.55x10-6

Background leavel : about 6x10-7

Far tail

Observation for the more out side

Bunch length monitoring by Opto-electric method

Er

Principal ofelectro-optical

samplingPD

1. Sampling:� simple analysis� balanced detector allows high sensitivity� good synchronization required� multi-shot method� arbitrary time window possible

Er

Principal oftemporal-

wavelength correlationcamera

2. Chirp laser method:� single shot method� some more effort for laser and laser diagnostics required � resolution due to laser ~ √t0· tchirp� time window ~ 1-20ps

Er

Principal oftemporal-spatial

correlationcamera

3. Spatial method:� single shot method� imaging optics is critical� resolution due to geometry > t0/cos(α)� time window ~ 1-20ps

Electro-Optical Sampling

TTF2 @ 140m

TTF2: Methods 1&2 installed at 140 m, method 3 will be used at 190 m

ElectroElectro--Optical SamplingOptical Sampling200 200 µµm ZnTe crystalm ZnTe crystal

ee−−

Ti:s laser

Ti:s Ti:s laserlaser

Adrian Cavalieri et al., Adrian Cavalieri et al., U. Mich.U. Mich.

SingleSingle--ShotShot

<300 fs<300 fs

170 fs rms170 fs rms

Timing JitterTiming Jitter(20 Shots)(20 Shots)

ee−− temporal information is encoded temporal information is encoded on transverse profile of laser beamon transverse profile of laser beam

Courtesy of J. Hastings